<?php

namespace App\Db;

class Select
{
    function from(){}

    function columns(){}

    function where(){}

    function orWhere(){}

    function orderBy(){}

    function groupBy(){}

    function limit($offset, $length){}

    function having(){}


    /* 聚集函数 */
    function count(){}

    function sum(){}

    function min(){}

    function avg(){}

    function distinct(){}
}